1. Field of the Invention
The present invention relates to optical information storage systems. In particular, the present invention relates to the holographic storage and retrieval of such information using optical disks.
2. Description of the Related Art
Optical memory disks have recently been developed as mass storage media in a number of audio-video and computer memory applications. In conventional systems the information stored on the optical disk is recorded and read out serially by focusing a laser beam on a single pixel with the aid of a lens. Unfortunately, this serial mode of data transfer limits the maximum operating speed of computers utilizing optical memory. Moreover, complex servo-mechanisms are typically required to keep the distance between the lens and disk constant to within approximately 1 .mu.m. as the disk rotates. As a result, the response time of the servo mechanism also effectively limits the maximum data transfer rate by limiting the angular velocity at which the disk can be rotated.
The optics included in conventional optical memory architectures also constrain the amount of information which can be stored on the optical disk. That is, the information storage density on the surface of the optical disk is limited by the resolution of the optical read-out system. Ideally, the maximum storage density would be limited only by the minimum dimensions recordable on the optical disk itself.
Hence, a need in the art exists for an optical information storage system not limited by serial-mode data transfer, and which can retrieve information without the aid of focusing optics.